Counterweight Position Optimization for Engine Vibration Reduction
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Solution Overview
Problem
Internal combustion engines with three cylinders experience vibrations that are not minimized by conventional counterweight arrangements, especially when the crankshaft axis does not coincide with the main axis of the powertrain's inertia matrix, leading to suboptimal NVH (noise, vibration, and harshness) properties.
Innovation Solution
The position and mass of counterweights in the counterweight arrangement are determined based on the inertia matrix of the drive train, deviating from the conventional 30° position relative to the first and third cylinders to optimize NVH properties by minimizing rotational acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If counterweights are positioned at the conventional 30° angle relative to the first and third cylinders, then the counterweight arrangement is simple and easy to manufacture, but the vibrations are not minimized when the crankshaft axis does not coincide with the main axis of the inertia matrix
Solution Approach 1:
The patent changes the counterweight position parameters from the conventional fixed 30° angle to optimized angles determined by the inertia matrix characteristics. Specifically, the counterweight angles are calculated based on the off-diagonal elements of the inertia matrix, allowing the positions to be adjusted to minimize vibrations when the crankshaft axis does not align with the main inertia axis.
2Object-affected harmful factors
If the crankshaft axis coincides with the main axis of the powertrain's inertia matrix, then conventional counterweight arrangements effectively reduce vibrations, but this alignment condition is not met in typical transverse motor vehicle installations
Solution Approach 1:
The patent applies local quality by determining counterweight positions specifically tailored to the actual inertia matrix characteristics of the powertrain. Instead of using a universal conventional angle, the counterweight angles are locally optimized based on the specific off-diagonal elements of the inertia matrix, making the solution adaptable to different installation configurations.
3Object-affected harmful factors
If counterweight position is optimized based on the inertia matrix, then vibration reduction is improved, but the determination process becomes more complex
Solution Approach 1:
The patent applies preliminary action by calculating and determining the optimal counterweight positions and masses before the engine is assembled or during the design phase. The inertia matrix is computed from the known powertrain parameters, and the counterweight characteristics are predetermined based on this computation, avoiding the need for complex real-time adjustments.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces vibrations in internal combustion engines by determining the ideal position and mass of counterweights, resulting in improved NVH properties even when the crankshaft axis does not align with the powertrain's main inertia axis, outperforming conventional arrangements.
Implementation Method 1
zwei Gegenmassen (21, 22), die dazu dienen, die durch die Schwungmassen der Kurbelwelle verursachten Trägheitskräfte zumindest teilweise auszugleichen
Implementation Method 2
die durch die Schwungmassen der Kurbelwelle verursachten Trägheitskräfte
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
Two counterweights partially compensate the inertia forces caused by rotating masses on the crankshaft while provided for the two outer cranks. One counterweight is arranged in a position which is rotated about the crankshaft axis with respect to an assigned crank through an angle which is the same of 30 degrees and a natural number or zero multiplied by 180 degrees. Independent claims are also included for the following: (1) an optimizing method for vibration behavior in an internal combustion engine; and (2) a vehicle system having a drivetrain to distribute power to propel the vehicle.